The invention relates to a device and a process for feeding combustion air required to burn coking gas that is released above the coal bed when coal is coked in coking plants with coking chambers, using the Non-Recovery process or Heat-Recovery process. The process described in this application is independent of the number of coke ovens, provided they form a battery. DE 102 01 985 A1, for example, describes a device of this type.
Heat Recovery coke ovens, as a rule, are heated by burning the gas obtained during the coking process. The combustion is controlled in such a manner that part of the gas is burned in the oven chamber above the coal inventory with the aid of primary air. This partly burned gas is conveyed through ducts also named “downcomer” to the heating flues arranged in the sole slab of the oven chamber and subsequently it is completely burned by adding further combustion air also named secondary air.
Hence, this method is used to transfer heat to the coal charge directly from above and indirectly from the lower side, an effect that is beneficial to the coking velocity and also to the performance of the oven. For the implementation of the process it is necessary that the air fed to the section above the coal charge (primary air) be exactly metered and varied in control via the duration of the coking period. In order to ensure a uniform heat development across the entire coal charge, it is necessary that the combustion air be dispersed in as fine a manner as possible across the entire coal charge.
According to the state-of-the-art technology, primary air is taken in through openings in the doors, the said openings being equipped with devices for manual adjustment of the air flow rate. In practice, however, the air taken in directly reacts upon entering the oven and the desired partial combustion thus cannot take place. Part of the coking gas instead undergoes an almost complete reaction near the air inlet openings of the doors, whereas the residual part of the coking gas is not burnt because of lack of oxygen.
Hence, the heat development is by no means uniform across the whole coal charge, which inevitably leads to an equivalent heat input with unfavourable heat distribution in the coal bed.